DNN (formerly DotNetNuke) is an open-source web content management platform (CMS) in the Microsoft ecosystem. A bypass has been identified for the previously known vulnerability CVE-2017-0929, allowing unauthenticated attackers to execute arbitrary GET requests against target systems, including internal or adjacent networks. This vulnerability facilitates a semi-blind SSRF attack, allowing attackers to make the target server send requests to internal or external URLs without viewing the full responses. Potential impacts include internal network reconnaissance, bypassing firewalls. This vulnerability is fixed in 9.13.8.
The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.